How the olfactory system makes sense of scents

The human nose is often considered something of a luxury, but in the rest o f the animal world, from bacteria to mammals, detecting chemicals in the en vironment has been critical to the successful organism. An indication of th e importance of olfactory systems is the significant proportion-as much as 4%-of the genomes of many higher eukaryotes that is devoted to encoding the proteins of smell. Growing interest in the detection of diverse compounds at single-molecule levels has made the olfactory system an important system for biological modelling.